1. Field of the Invention
The present invention relates to a retractable safety syringe having a simple structure, which allows ready assembly and safe use and disposal of the syringe so as to prohibit re-use of the syringe.
2. Description of Related Art
Hypodermic syringes are used to deliver medicine fluids in a safe and hygienic manner to patients. However it is found that for various reasons some syringes are re-used and this can result in transfer of diseases to the people injected with the re-used syringes. Thus there are various single-use-only safety syringes designed and produced to enable users to readily operate and dispose the syringes after finishing an injection procedure. The conventional safety syringe comprises a retractable needle which allows the needle to be connected with the plunger rod and retracted into the syringe barrel after finishing of the injection procedure.
However, the conventional safety retractable syringes still have some disadvantages which are as follow.
1. Most of the conventional retractable safety syringes are difficult to use due to their complex structure and multi-components configuration. The complex structure of the conventional syringe also decreases the efficiency of manufacturing and increases the manufacturing costs.
2. Some conventional syringes still have medicine residue in the syringe barrel when the plunger rod is fully extended into the syringe barrel, so that the needle is not properly connected with the plunger rod, which results in that the needle can not be retracted into the syringe barrel.
3. Also because of the complicated structure of some conventional syringes, the medicine fluid is not able to directly flow from the barrel towards the needle of the syringe, whereby some air bubbles occur in the medicine fluid. These bubbles can be harmful to a patient who may already be in poor health.
Therefore, it is an objective of the invention to provide an improved single-use-only and disposable retractable safety syringe to mitigate and/or obviate the aforementioned problems.
The main object of the present invention is to provide an improved retractable safety syringe comprising a needle mount fixed at an upper end of a syringe barrel, a plunger rod movably fitted in the syringe barrel and a needle fixed on the needle mount. Wherein the needle mount is integrated with an outer hub and an inner hub, the inner hub has a plurality equal-spaced spring clamps formed at a lower end of a fluid passage defined in a center thereof. The plunger rod consists of a rod and a plunger detachably connected at an upper end of the rod. The plunger is formed with a plunger crown having a cone-shaped tip end portion formed on a top thereof and a neck portion formed between the tip end portion and the plunger crown. When the plunger rod is fully fitted into the syringe barrel, the tip end portion is inserted into the fluid passage, and the neck portion is clamped by the spring clamps. The medicine fluid retained in the syringe barrel is able to flow over gaps between each two adjacent spring clamps, therefore the medicine fluid retention in the syringe is minimized, and the needle and needle mount are able to be retracted into the syringe barrel after finishing an injection procedure.
A further object of the invention is to provide an improved retractable safety syringe having a configuration feature that ensures ready assembly and use of the syringe.
Yet another object of the invention is to provide an improved retractable safety syringe having a simple structure, which enables the medicine fluid to directly flow in a substantially direct way from the syringe barrel over the fluid passage towards the needle.
Other objects, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.